Eventos Anais de eventos
DINAME 2017
XVII International Symposium on Dynamic Problems of Mechanics
Stochastic parametric analysis: a new approach to stick-slip oscillations
Submission Author:
Roberta Lima , RJ , Brazil
Co-Authors:
Roberta Lima, Rubens Sampaio
Presenter: Roberta Lima
doi://10.26678/ABCM.DINAME2017.DIN17-0032
Abstract
In this paper a parametric analysis of a sample of responses of a dry-friction oscillator is performed in order to construct a statistical model. The system consists of a simple oscillator (mass-spring) moving on a base with a rough surface. Due to this roughness, the mass is subject to a dry-frictional force modeled as a Coulomb friction. It is considered that the base has an imposed stochastic bang-bang motion which excites the system in a stochastic way. The base velocity is modeled by a Poisson process for which a probabilistic model is fully specified. The non-smooth behavior of the dry-frictional force associated with the non-smooth stochastic base motion induces in the system stochastic stick-slip oscillations. The system response is composed by a random sequence alternating stick and slip-modes. With realizations of the system, a statistical model is constructed for this sequence. In this statistical model, the variables of interest of the sequence are modeled as random variables, as for example, the number of time intervals in which stick or slip occur, the instants at which they begin, and their duration. Samples of the system response are computed by integration of the dynamic equation of the system using independent samples of the base motion. Statistics and histograms of the random variables which characterize the stick-slip process are estimated for the generated samples. The objective of the paper is to analyze how these estimated statistics and histograms vary with the system parameters, i.e., to make a parametric analysis of the statistical model of the stick-slip process.
Keywords
stick-slip, stick duration, dry-friction oscillator, statistical model, Parametric analysis
